1. Field of the Invention
The present invention relates to a nicotianamine aminotransferase, a gene therefor and utilization thereof.
2. Description of Related Art
Calcareous soil, a saline illuviation soil in dry ground, occupies about 30% of the soil in the world, including China, the Middle and Near East countries, the Central and North Africa, the Central and West America and soon. In this soil, iron in the soil is insolubilized due to a high pH. A plant can not grow in this soil, developing chlorosis by iron deficiency, unless it can absorb iron in soluble form from the root by any means. When agriculture and environmental afforestation are desired, measures against the deficiency of soluble iron in the soil will be an important problem.
As measures to solve the iron deficiency of plant by agricultural technique, it may be considered (1) to correct pH of the alkaline soil to neutral or slightly acidic one by addition of sulfur, (2) to apply a substance containing a chelated iron or (3) to increase soluble iron in the soil by enhancing soil microorganism activity, for example, by means of application of an organic substance, thereby increasing siderophore (an iron transporter) production by the microorganism.
These means for providing iron by soil treatment, however, are not always satisfactory because there are problems, for example, that a large amount of application material is required, that the effect is very unstable depending on the method of application including time of application, site of application, concentration, kind of spreader or the like and weather conditions. Therefore, development of novel techniques has been demanded.
Under these circumstances, the present inventors have conducted extensive studies and discovered a novel gene which is suitable for enhancing absorption ability on insoluble iron in soil and improving resistance to iron deficiency and thus have completed the present invention.